Advancements in the fields of electronics and communications have permitted the introduction and commercialization of many new types of communication systems. Information can be affordably communicated to locations in manners previously not possible or affordable.
The field of cellular telephony is exemplary of a communication system that has been made possible due to such advancements. Communication using a cellular telephone or other radiotelephonic system is advantageous because a fixed, wireline connection is not required between a sending station and receiving station to permit communications to be effectuated therebetween. A cellular or other radiotelephonic communication system is therefore particularly advantageous to effectuate communications when the use of fixed or hard-wired connections would be inconvenient or impractical. Continued advancements in the field of cellular telephony, as well as other types of radiotelephonic communications, have permitted the introduction of new services and new forms of communication pursuant to already-installed cellular, and other radiotelephonic, networks.
Proposals have been set forth to provide existing cellular, and other communication networks, with the capability of communicating packet data. Information to be transmitted between a sending station and a receiving station is formed into discrete packets of data. Individual packets can be sent on a communication channel from the sending station to the receiving station. Because the information is communicated by way of discrete packets, the sending station need utilize the channel only during the time periods required to send the discrete packets. A channel is typically, therefore, a shared channel used by a plurality of sending stations.
To communicate a packet of data to a mobile station (MS), the packet must be addressed with an identification address of the mobile station. An Internet Protocol (IP) address is exemplary of an identification address that can be used to address packets of data that are to be relayed to the mobile station. The IP address is, of course, utilized when transmissions are made pursuant to an Internet Protocol. Many different types of services have been implemented that are effectuated by the communication of packet data according to various other protocols.
Transmission Control Protocol/Internet Protocol (TCP/IP) is the protocol of the Internet and has become the global standard for communications. TCP provides transport functions that insure that the total amount of bytes sent is received correctly, while IP provides a routing mechanism. TCP/IP is a routeable protocol, which means that messages contain not only the address of a destination station, but also the address of a destination network. Every user in a TCP/IP network requires an IP address. In Simple IP, which is used by non-mobile Internet users, a new IP address is dynamically assigned every time a user negotiates a point-to-point protocol session.
Point-to-point Protocol (PPP) is a protocol that provides point-to-point access and enables networking over serial lines. The cdma2000 wireless communication standard is a third generation technology that increases data transmission rates in CDMA (code division multiple access) systems. Point-to-point protocol is the protocol used by the cdma2000 wireless communication standard for communications between, for example, mobile stations and packet data service nodes (PDSNs). A packet data transfer session using point-to-point protocol between a mobile station and a packet data service node is referred to as a point-to-point protocol session.
In order for a mobile station to gain access to the Internet, an air interface between the mobile station and a radio network (RN) and a connection between the radio network and the packet data service node over an radio-network-packet-data-service-node (R-P) interface must be established. When the mobile station is involved in a point-to-point protocol session using the air interface and the R-P interface, the connection is collectively referred to as a point-to-point protocol (PPP) connection.
Point-to-point protocol comprises several sub-protocols, including the link control protocol (LCP) and several network control protocols. Which of the sub-protocols other than link control protocol is used depends on the type of traffic that is to be sent over the point-to-point protocol connection. Link control protocol, which is used for link establishment, configuration, and testing, is the only one of the sub-protocols of point-to-point protocol that is employed every time a point-to-point protocol session is negotiated.
The term “full point-to-point protocol negotiation” refers to a point-to-point protocol negotiation that includes negotiation of the link control protocol and potentially includes negotiation of one or more of the other sub-protocols that comprise the point-to-point protocol. In a full point-to-point protocol negotiation, link control protocol negotiation must reach a certain stage before the other sub-protocols comprising point-to-point protocol can be negotiated. Furthermore, the full point-to-point protocol negotiation must be performed every time the mobile station initiates a point-to-point protocol session, including when the mobile station is involved in a handover between packet data service nodes.
When link control protocol options are negotiated, a first peer (e.g., a mobile station) sends to a second peer (e.g., a PDSN) a request (REQ) message that includes an option number that identifies a particular link control protocol option. The link control protocol option includes certain parameters (typically referred to as options), such as, for example, maximum transmit unit and authentication method, that the first peer requests to use during that particular point-to-point protocol session. Either of the peers can send the REQ message. Next, the second peer examines the option and the parameters and, if the parameters are satisfactory to the second peer, the second peer replies to the first peer with an acknowledge (ACK) message, which indicates to the first peer that the option and parameters have been accepted by the second peer.
If the option is not supported by the second peer, the second peer sends a rejection (REJ) message to the first peer. If the second peer supports the option but one or more of the parameters is not acceptable to the second peer, the second peer sends a negative acknowledge (NAK) message to the first peer that identifies a second set of parameters that are acceptable to the second peer. If the second set of parameters is acceptable to the first peer, the first peer replies to the second peer with an ACK message.
When the mobile station is engaged in a point-to-point protocol session, the mobile station will often need to be handed over between different cells of the wireless communication system as the mobile station roams. Sometimes these handovers of the mobile station require that handling of the point-to-point protocol session be transferred from a first packet data service node to a second packet data service node. Such inter-packet-data-service-node handovers typically occur when, following the handover, the radio network serving the mobile station cannot connect to the first packet data service node such as, for example, when the radio network is not aware of the first packet data service node, when the radio network belongs to an operator that does not wish to use the first packet data service node, or when the network topology does not allow the radio network to reach the first packet data service node.
In connection with the inter-packet-data-service-node handover, the point-to-point protocol session begun prior to the handover must be fully negotiated again even though most often the point-to-point protocol parameters (e.g., PPP options) are limited to only a few choices and seldom change. The point-to-point protocol parameters very frequently have the same characteristics when the mobile station is served by the first packet data service node as when the mobile station is served by the second packet data service node.
Since the point-to-point protocol negotiation parameters of mobile stations seldom change, full point-to-point protocol negotiation is often unnecessary and constitutes a significant waste of time and system resources. This is especially true when a poorly-performing air interface between the mobile station and the radio network causes data packets to be lost during the full point-to-point protocol negotiation, resulting in numerous packet retransmissions. Delays due to these data packet retransmissions may be long enough to cause failures in real-time applications that are running on the mobile station, especially during inter-packet-data-service-node handovers.
There is accordingly a need for a method and system for faster and more reliable mobile station point-to-point protocol negotiation upon the mobile station beginning a new point-to-point protocol session or being handed over between packet data service nodes.